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wtb A14 headers

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A12 manifold is smaller volume (less flow) than A14 manifold. They bolt up the same, but the internal volume differs.



And I should have pointed out that the manifold we flow-benched was an early A14 manifold (heat riser shaved, ceramic coated, and smog ports capped). :P



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Well now I am confused. First you state that you and a freind bench tested a "1200" manifold against two headers and the "1200" manifold won. And now you say you should have mentioned it was an "early A14" manifold that was tested, we all know wether "early" or late model run "A14"='s 1400 not "1200" no matter how you slice it.


I am just triing to have a little fun with my 78 B210 project, I am not triing to dispute or test anyones understanding of how exaust gases exit a car.


Which brings me back to "WTB A14 header" or is that to difficult a concept.

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  • 2 weeks later...

Well how much are you looking to spend on a header? There is some shaving you will have to do in order to make it fit perfectly. SOme Intake manifold shaving. If i can get a stock Manifold + Cash $$$ we can work something out. they are pretty rare for the A-series engines.

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  • 7 months later...

FWIW #2, when my shop mate Tim had his head ported and flow-benched we decided to flow bench two headers (small port shorty and large port long-tube) versus the stock 1200 manifold. Up to 6000-6200rpm, the stock exhaust manifold out-flowed both headers.


Sorry to bump a thread, but exhaust flow numbers arent everything when it comes to performance. It has just as much to do with exhaust scavenging, if not more. Why do you think any small engine (anything from lawnmowers to MX bikes) will either not run at all or run like garbage with either too big/short of an exhaust or no exhaust? The exhaust pulses have to be balanced. Cylinder 1 is partnered with 3 and 2 is with 4 in a tri-y in a 1-3-4-2 engine to maximize this. In a correctly tuned header system, when one cylinder's exhaust gases are at the end of the primaries (the first y), the partnered cylinder is just starting its exhaust stroke and the gases are being siphoned by the vacuum created by the passing gases at the meeting point of the two primaries. The stock manifold "flows" because it just allows all cylinders to dump their exhaust in a big chamber without much regard for scavenging. If you have a header than can scavenge and flow, you've hit the jackpot. Higher compression engines require relatively less scavenging than lower compression for the simple fact that everything is higher pressure and as a consequence they need in a lot of cases, a bigger header.

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  • 1 month later...

I can verify this. I have one of Bill's headers and had to hammer it to clear the steering box with my A12. When I swapped in my A15 and 5-speed I had to do some clearancing by the bellhousing. I also had to weld and grind at the flange to fix a persistent leak. Mine came in a Thunderbird box and the newspapers used for packing were dated 1978. They are what they are. Unfortunately there aren't a whole lot of options out there. Sorry, I don't have a spare to sell but I wanted you to be an informed consumer.


On a side note, when I bought mine off eBay (from Bill's) the opening bid was $150 and I was the only one. I don't think I would have been very satisfied paying any more than that. I picked it up in person. He's VERY proud of his products and his "skills".


Even good quality headers can leak. Poor quality headers can/will leak so much that they are dangerous when used in an enclosed car. Headers that leak are fine for a racing car with open windows, but not for a street car. Keep your stock cast iron exhaust manifold and save weight somewhere else, you will be glad you did.



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Because they're 2-stroke engines. ;)


Exhaust is EVERYTHING on a 2-stroke.


most lawnmowers are 4-strokes, alot of dirtbikes and most 4 wheelers are 4 strokes, a growing trend is 4 stroke weedeaters. so they arent all two strokes. exhaust IS everything on a 2 stroke, but on a 4 stroke it matters almost as much. if you have a properly ported exhaust port and a properly set up exhaust system to match, then it actually can do more than say putting a down draft weber on or a single side draft set up. its been proven that an expansion chamber exhaust that uses the same principal as a two stroke MX exhaust (tuned differently of course) can improve the performance of a 4 stroke dirt bike noticeably with no other mods. and no the header may not flow quite as well as the stock manifold but to illustrate what the inside of the manifold looks like a little better:


now the best way i can describe how terrible this is would be like making a rectangular prism out of steel and cutting 4 holes in it and putting square tubing from each exhaust port directly into that box. and then cutting a larger hole in the back and that goes to the rest of the exhaust. yes, it might flow pretty well, but how in the world would that make performance.

next up we have headers, both types 4-1 and 4-2-1 or tri-y.


yes i understand the pictures dont depict the proper proportions of the primaries and secondaries and so on but even the 4-1 header will flow better than the stock manifold if it has larger pipes. if the 4-2-1 is set up properly, then the exhaust pulses are balanced and the cylinders in both cylinder "banks" (cylinders opposite from each other in terms of firing order, and in turn exhaust strokes) will take turns literally siphoning the other cylinders exhaust pulses out of the cylinder and the two banks do the same for each other in the secondaries, the 1/4 bank siphons for the 2/3 bank and then they return the favor for the other. the stock manifold does nothing in that respect. there are lots of benefits of increased scavenging. The main one being increased torque. you can move more air into the combustion chamber with no intake mods because the exiting exhaust creates a vacuum as its leaving and you wouldnt need any extra valve overlap to do so with a properly set up header. there are ways of getting a happy medium between great torque and great horsepower, but thats a whole other subject.

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